幽门螺杆菌耐药性与细胞毒相关基因A分型关系

CagA genotype and drug resistance of Helicobacter pylori

目的探讨对克拉霉素耐药的幽门螺杆菌(Hp)携带细胞毒相关基因A(CagA)状况及其与基因分型的关系。方法收集右江民族医学院附属医院确诊Hp感染患者的胃窦部黏膜标本482份,进行Hp分离培养和鉴定;采用PCR方法扩增CagA,采用E实验(E-test)进行克拉霉素耐药试验,采用细菌基因组重复性元件序列PCR技术(REP-PCR)方法对携带CagA+的克拉霉素耐药株进行基因分型,运用NTsys_2软件进行聚类分析。结果分离培养出374株Hp,其中CagA阳性87株,阳性率23.3%;随即选取携带CagA基因的克拉霉素耐药的26株Hp,根据78%的相似性分析结果显示,可分成6类基因型,分别是GroupⅠ、Group II、GroupⅢ、GroupⅢ、GroupⅣ、GroupⅤ,GroupⅥ,每类分别有3、3、8、4、6、2株Hp。结论携带CagA基因的克拉霉素耐药的Hp可分成6类基因型,Hp的克拉霉素耐药性基因分型与CagA基因无密切关联。

Objective To study the genotype of CagA and drug resistance to clarithromycin of Helicobacter pylori（Hp）.Methods Hp strains were isolated from 482 gastric mucosa biopsies of patients with peptic ulcer or gastritis in Youjiang Medical College for Nationalities.The amplification of CagA gene fragment was conducted with PCR.Resistance to clarithromycin of Hp was determined with E-test.Meanwhile,strains were genotyped with repetitive extragenic palindromic-PCR（REP-PCR） and further clustered with NTsys_2 software.Results Totally 374 Hp strains were identified with 87 Hp strains of CagA gene positive and a positive rate of 23.3%（87/374）.The 26 CagA gene positive and resistant to clarithromycin strains were divided into six genotype groups according to their 78% homology,with 3,3,8,4,6,2 strains in each Hp group,respectively.Conclusion The CagA gene positive and resistant to clarithromycin strains could be divided into six genotype groups and the resistance to clarithromycin of Hp is not associated with CagA gene.